Sometimes, when pushed, veterans of war tell of the unspoken bond that exists between those who have "been there".

Fred Smith is no soldier, but he has been there, sharing the taste of the dust, danger and death that has been the daily fare for Australia's troops serving in Afghanistan.

He's also given a voice to many of those who've served their country overseas but struggle to find the words to describe the impact it has made on their lives.

"He sort of says what soldiers don't," says Dean West, who served with 57-RAR in Malaysia in the early 1990s. "Yeah, it's our feelings. He's knocked it on the head. It's us."

Five years ago, Mr Smith became Australia's first foreign affairs official to be sent into work alongside ADF personnel stationed in the volatile Uruzgan province.

When he returned to Australia this week, at the end of another six-month tour, he also became the last.

But Mr Smith's diplomatic role in the war-torn nation is only one part of his connection with veterans of this conflict and others.

The man who has been dubbed the singing diplomat, is an accomplished entertainer, songwriter and musician, and it's his music that has resonated with those he has met in Afghanistan and at home - songs like Dust Of Uruzgan and The Sapper's Lullaby.

It comes from a certain angle and I don't think many people were expecting it to hit as many chords as it has. You think, wow, this is actually a piece of music that's not so much music, it's more like poetry.

Veteran Jamie Whitehead

"It comes from a certain angle and I don't think many people were expecting it to hit as many chords as it has," says another veteran, Jamie Whitehead, who served with the Navy in Kuwait.

"You think, wow, this is actually a piece of music that's not so much music, it's more like poetry."

Last weekend in Tarin Kot, at an event secretly organised by the ADF, Mr Smith performed his new song, Going Home, in front of 57 family members of the 40 Australians killed in Afghanistan.

The song explores the complex emotions that many defence personnel experience when it's time to finish their active service.

"I think Fred has the uncanny ability to capture the essence of a feeling or an anxiety," says Michael Balfour, a Griffith University professor who works closely with ADF veterans.

"The song is about life in Afghanistan but also about the anxiety about coming home to a family who they love and to a family who loves them, and in a sense that is one of the greatest fears for some of them, about how they are going to re-integrate back into civilian life and back into their old lives.

"So the song is really just capturing that feeling and that anxiety and saying this may or may not be a problem, but it’s good to acknowledge the fact that these are feelings that everyone is experiencing."

Numbers of veterans needing help expected to rise

Proceeds from the sale of Going Home are being donated to a Brisbane-based support group, Mates4Mates. It was set up in March to help serving and former ADF personnel overcome physical and mental injury.

The number of veterans using the service has tripled in the past four months, and as Australia's involvement in Afghanistan winds up, it is expected the number of those needing assistance will continue to grow.

"It has the potential to look like Vietnam," says Janice Johnson, a psychologist provide counselling services at Mates4Mates.

"Thirty per cent of Vietnam vets went on to develop post-traumatic stress disorder (PTSD), so most of us are anticipating that it has the potential to be a figure like that.

"When we extract the force out of theatre, the percentages of those with PTSD is quite low - it's about 1 per cent, conservatively, at that point in time - but by its very nature, post-traumatic stress comes later. It builds across time.

"Early intervention is the key. If you can get in early and do the things to treat post-traumatic stress, well then hopefully we don't get that 30 per cent."

A PTSD sufferer himself, Mr Whitehead often counsels younger veterans about dealing with their inner demons.

"A lot of people are suffering certain things, but they need to be dealt with in a certain type of way," he says, "going on the booze with your mates and doing those sorts of things, they don't help at all.

"I know a lot of the guys from Vietnam had this stigma attached. Now it's recognised, it's the injury that can be treated, it doesn't have to be a permanent injury. It's something that you need to embrace and move forward. It's not a death sentence."

Songs can help those suffering in silence

Professor Balfour has been using theatre and social media to help encourage veterans to open up about their inner turmoil, but he believes songs like Mr Smith's can help reach still more suffering in silence.

Cold Chisel's Khe Sanh and Redgum's I Was Only 19 are just two that have helped generations of Australians to understand the lasting impact of war.

If one person that listens to that song can come away from it saying, 'That's my story', or if they can go away from it thinking, 'You know what, I'm not alone', then that's what's important and the song has done its job.

Professor Michael Balfour

"A song can cut through the essence of the issue in the way that other media just can't. It can create a moment of insight, a moment of connection, a moment of resonance with an audience," Professor Balfour said.

"It's what we don't want to tell anyone," confides Dean West, who also believes Mr Smith's work will become iconic songs for today's generation of veterans.

"The song I Was Only 19 came out for the Vietnam era and these songs have come out for us.

"You go up to a soldier and ask, 'How was your trip to Afghanistan?', and all that sort of stuff and it's like one-word answers - 'Yeah, it was good' - stuff like that.

"But if you listen to his songs, it's stuff like - 'This is what we did, we went out on patrol, we were sort of scared or nervous, but we had fun as well' - all that sort of stuff; it's kind of talking straight to us."

"If one person that listens to that song can come away from it saying, 'That's my story', or if they can go away from it thinking, 'You know what, I'm not alone', then that's what's important and the song has done its job."

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The road to radicalisation

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In January 2014, a young Australian couple was gunned down in Aleppo by rival rebel Syrian forces.Amira Karroum and her husband Tyler Casey were devout Muslims who travelled to Syria to join the global jihad.But how do a boy from the Brisbane suburbs and a girl from the Gold Coast beaches end up dead in one of the world's most brutal conflicts?

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Amira Karroum was born to a New Zealand mother and a secular Muslim father, who fled Lebanon to Australia and founded a multi-million-dollar restaurant business on the Gold Coast. She attended the exclusive Gold Coast Anglican private girls' school St Hilda's, before going on to study graphic design at QUT.Amira's teen years sunbathing on the beach, going to nightclubs and working at Sea World were a world away from the radical cause she would take up a few years later.

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Tyler Casey was born in Adelaide in 1990. As a small child he moved to Redcliffe, just north of Brisbane, where his mother married a recovering drug addict. Casey and his three younger half-brothers had a tumultuous upbringing in a fundamentalist Christian home.At 13, he moved with his mother to the United States. Separated from his younger brothers, he became involved in gangs and petty crime in the city of Colorado Springs. It was there he began his first steps on the path that would lead to an unmarked grave in Syria.

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Unbeknownst to his family, during his time in the US, Casey began to associate with followers of a senior Al Qaeda Anwar Al Awlaki, who had previously been based in Colorado and later died in Yemen; Australian authorities believe he became an international emissary for Al Qaeda. From 2008, he was paid by Al Qaeda in the Arabian Peninsula to travel to Egypt and Yemen, where US intelligence agencies report he was trained for warfare. He was also sent to South Africa for religious training in 2011, where he was filmed in the audience of a sermon by one of Syria's most prominent anti-government sheikhs, Muhammad Al Yaqoubi.

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Amira and Casey's paths crossed after each moved to Sydney. In her late teens, Amira moved with her sister to be closer to her Muslim relatives in Sydney's west.One of her cousins was Fadl Sayadi, who served five years in jail for being a senior player in the biggest terrorism plot in Australia's history. Another cousin was Bilal Sayadi, who had a history of crime dating back to his teens, including bashings, drug offences and a shooting.Casey had taken on the name Yusuf Ali and became a street preacher, converting Australians to Islam with other devout young men involved in the Street Dawah movement.It was through Street Dawah that he became close friends with another street preacher, Bilal Sayadi.

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Bilal Sayadi arranged a marriage between Amira and Casey and a romance blossomed - but police soon discovered the marriage was part of a bigger plot. For the couple, it was another step along the path to becoming a soldier of Islam.Amira began posting increasingly extreme statements to Facebook, writing "the hereafter is coming" and "Jannah [or paradise] is my destination". Another post said "democracy is cancer, Khilafah [the Islamic caliphate] is the answer".Months after the pair married, Casey told friends he was going to fight alongside Al Qaeda and wouldn't be returning to Australia or the US.Casey's stepfather reported his plan to the Australian authorities, but on June 29, 2013 he flew to Turkey via Singapore.

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During his time at Street Dawah, Casey had met fellow jihadist Mohammad Ali Baryalei, a leader of the Street Dawah movement who would emerge as a pivotal figure drawing young Australians to Syria.It was Baryalei, now based in Syria, Iraq and Turkey, who would facilitate Casey's journey to the Syrian battlefield, along with three other young Australians.Australian authorities say Baryalei has become the most senior Australian member of the Islamic State militant group in Syria and Iraq, responsible for funnelling at least half of the 60 Australians currently fighting there onto the frontline. Family of the 33-year-old Afghan refugee and former Kings Cross nightclub bouncer say he claims to be living a peaceful life in Turkey.

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Phone calls intercepted by police tell the story of the group's journey to the battlefield.From Turkey, they crossed the border to Syria in early July, where they were given battle training by Jabhat Al Nusra, an Al Qaeda affiliate fighting Assad's forces in Syria.As with this latest generation of jihadists, Casey embraced technology from the frontline, staying in close contact with his brother, showing off his cache of weapons - including AK-47s and hand grenades via Skype.

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Meanwhile, Amira was planning on joining her husband, telling her father she wanted to be a fighter.Under the guise of a trip to visit friends in Denmark, which was funded by her cousin Bilal Sayadi, she planned to make her way south to Syria.Police halted her first effort to leave the country, but the next day, with the assistance of her lawyer, she left for Denmark, where she met up with other Islamists making the journey to Syria.Amira and Casey were reunited in January 2014, but instead of fighting Assad, they became embroiled in a fierce power struggle between rival rebel groups.

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Just days after Amira's arrival in the rebel stronghold of Aleppo, they were ambushed and executed in a makeshift home they shared with a Somali couple.Australian authorities say in a brutal takeover of their Australian Jabhat Al Nusra contingent, the house was surrounded by IS militants wielding automatic weapons and Amira and her husband were killed in a blaze of gunfire.Her father had a heart attack upon hearing the news, saying he received a call from Syria telling him his daughter's body had been dismembered and the Somali couple was buried alive.Within days, Casey's fellow fighters had joined Islamic State.